Thread protector



Oct. 24, 1933. H, E, MCCRERY 1,931,703

THREAD PROTECTOR Filed April 18, 1931 2 Sheets-Sheet l INVENTOR M 5M v M Oct. 24, 1933. H. E. McCRERY 1,931,703

THREAD PROTECTOR Filed April 18, 1931 2 Sheets-Sheet 2 INVENTOR Patented Get. 24, 1933 urr- TATES THREAD PROTECTOR Harold E. McCrery, Pittsburgh, Pa., assignor to Blaw-Knox Company, Pittsburgh, Pa., a poraticn of New Jersey Application April is, 1931. SerialNo. 531,101

4 Claims.

This invention relates to thread protectors and provides desirable features of construction for both inside and outside protectors. This applicaticn is a continuation in part of my copend- 5 ing application Serial No. 452,589, filed May 15,

1930. A thread protector to be commercially desirable should, in addition to giving adequate protection, be relatively inexpensive to manufac- '10 ture, simple to apply and remove, and of such form that there is no danger of the hands of a workman being torn either in placing or removing the protector, or in handling pipes to which it is applied.

In order to completely fulfill the requirements of the trade there should be provided a protector for the outside threads on a pipe proper and a protector for the inside threads on a coupling. In this specification I refer to either the pipe or the coupling as a pipe member.

One marked difficulty in protectors heretofore employed lies in the fact that the threads thereon are such that they lack adequate strength, or else show such a strong tendency to bind that frequently a pipe member is destroyed in an attempt to remove the protector. Where it has been attempted to reduce the frictional resistance of the threads to unscrewing of the protector, it has been been found that the protectors will sometimes rattle or shake off. Further difficulties arise from the scoring or galling of the threads by such thread portions on the protectors, and delays in application of the protector by reason of so-called cross threading. By this I mean the tendency of a protector to engage the pipe member While mis-alined, it being very easy to turn the protector for a few threads, after which jamming occurs, making it necessary to remove and re-insert the protector.

I overcome all these difiiculties by employing a thread having portions of different pitch. Preferably "I employ a protector having a body of thin wrought metal, an edge of which is flanged to form a thread. This thread preferably extends substantially all the way around the protector so as to avoid any danger of cross threading. In orderto insure against the protector shaking off, I make a portion of the thread on the protector of a different pitch from that of the thread which it is to engage. There is obtained just enough binding action to securely hold th protector in place, and the binding action may be enhanced, if desired, by having the thread on the protector terminate on a relatively sharp end.

The protector may be readily applied. It cant not be wrongly inserted and may be readily spun into approximately its final position. An abut- .ment is provided-to engage the pipe member and limitthe amount in which the protector is threaded thereon. The body of the protector between the abutment and the thread is made to lie clear of the pipe member. This is particularly important with the form of thread which I employ, for tightening of the protector results in a slight distortion of the protector, which distortion strains the metal and provides enough frictional resistance to hold the protector in its applied po sition under all practical conditions.

' Nevertheless, a slight turning of the protector relieves it of such distortion and it may thereafter be readily removed.

It is desirable to provide adequate protection for the end of the pipe member. I prefer to employ a roll of metal at the end of the protector, which roll is ,of a diameter greater than the diameter of the pipe. inherently capable of withstandingv blows. The roll is preferably carried radially inwardly; so as to provide adequate protection for the end and is preferably turned to form a longitudinally extending inside flange. This places theedge of the metal in such position that it ispractically impossible for a workman to cut or tear his hands. It also materially simplifies the handling of the pipes. It is common practice in unloading pipe for the workmen to employ sticks which they thrust into the end of the pipe for lifting it. When the pipe has been moved the-sticks are slid out. This is difficult if a raw edge of metal engages the stick, but is very simple with my construction. In certain cases, particularly in thecase of the protector for outside threads, it may be desirable to make the roll on a separate cap. Where this is done I prefer to unite the cap and the body by means of a bead which stifiens the protector and permanently unites the parts thereof. Where a cap is employed I prefer that the thread lie between the planes which define its ends. The cap is preferably of relatively heavier metal to insure adequate protection.

To avoid any tendency toward accumulation of water in the roll I provide drain openings which are so spaced as to prevent water ever accumulating to sufiicient depth to engage the pipe. This insures against rusting of the pipe and eliminates any danger of the protector becoming stuck by rusting.

In the accompanying drawings illustrating present preferred embodiments of my invention,

By reason of its shape it is Figure 1 is a longitudinal section partly broken away, showing an outside protector;

Figure 2 is an end View thereof;

Figure 3 is a view corresponding to Figure 1 but showing the protector applied to a pipe;

Figure 1 is a transverse section through a protector for inside threads;

Figure 5 is an end View thereof; and

Figure 6 is a view corresponding to Figure 4 but showing the protector applied to a pipe coupling.

Figures 1 to 3 inclusive show the outside protector. It comprises a sleeve 2 adapted to lie over the threaded end of a pipe P. One edge of the sleeve 2 is rolled to form a reinforcing bead 3, and the other edge is turned inwardly to form a thread 4. The thread is generally helical in shape, corresponding to the helix of the pipe thread, but one portion la thereof departs from this helical form so that a binding action on the pipe thread is obtained. It will be noted that the portion 2a of the sleeve adjacent the thread flange 4 lies clear of the pipe P. It will be seen that when the protector is applied the portion la of the thread flange will necessarily be somewhat distorted. This distortion is reflected back through the portion 2a of the sleeve and by reason of the clearance thereof from the pipe no binding beyond that desired in the thread flange occurs.

It will be noted from Figure 2 that the thread flange 4 extends substantially all the way around the protector. One or" the ends 5 of the thread flange is sharpened so as to improve the locking action.

A cap 6 is secured to the body 2. The cap, like the body 2, is made of thin wrought metal. The parts may be drawn from sheet metal or may be formed from thin tubing. It will be noted that the cap 6 is made of metal somewhat thicker than the sleeve 2. The cap and the sleeve are permanently connected together by forming a hump '7 in the metal of each, this hump constituting a tector.

bead which looks the sleeve and the cap together and prevents relative rotation thereof.

form an axially extending inner flange 10. In

this way the edge 11 of the metal is so placed that it cannot injure the hands of a workman. The end face 9 of the protector engages the pipe when the protector is threaded to its final position, and the flange 10 is of such diameter as to lie just inside the pipe wall, thus aiding in transmitting force from the protector to the pipe member. A

While the threads of the pipe usually receive a coating of oil during cutting and are therefore not likely to rust immediately, it is most desirable that there be no accumulation of water which would wet the threads and tend to rust them. In order to prevent any accumulation of 'water in the roll 8,1 provide drain openings 12 in the periphery of the roll. The position of these drain openings is shown by dot and dash lines in Figure 2, and the maximum depth to which water can accumulate in the roll is represented by the line W-W. It will be seen from to bathe the threads on the pipe.

Figures 4 to 6 inclusive show the inside pro- Whereas in the case of the outside protector the body is made up of the cap and 6 sleeve, the entire protector of Figures 4 to 6 is made in a single piece. The thread 13 is similar to the thread of the outside protector; that is to say, it extends substantially all the Way around the protector and, in part, is a helix corresponding to the thread of the pipe coupling 0, and, in part, is of non-helical form so as to obtain the desired binding action. The angularity of the respective thread portions is illustrated by extended lines in Figure 4.

When the thread protector is inserted a face 1% obtained by flaring of the body of the protector in the form of a frustrum of a cone engages the tapered face F of the coupling C. The body portion 15, lying between the face 14 and the face to form the axially extending inner flange 19.

My protector in either of its forms may be readily handled either on or off the pipe member without danger to the workmen. It may be quickly applied and quickly removed, although it shows a marked ability to stay in place until removal is intended. By reason of its shape it stands an almost unbelievable amount of battering. It is light in weight and may be manufactured at relatively low cost. There is no danger of it rusting to the threads by reason of an accumulation of water. If desired, it may be dipped in a rust-resistant compound, such as a protecting oil, before use. Usually, however, there will be enough oil accumulated on it from the die work to give all the'protection necessary.

I .have illustrated and described the present preferred embodiments of the invention, but it will be understood that it is not limited to the forms shown as it may be otherwise embodied within the scope of the following claims.

I claim: V

1. A thread protector comprising a sleeve shaped to lie against and longitudinally of the pipe member to which it is to be applied, said sleeve having its edge nearest the end of the pipe to be protected turned at an angle to the body thereof to form a thread adapted to engage the thread of the pipe member, and a cap having a skirt engaging the sleeve and a portion shaped to extend over and engage and protect the end of the pipe.

2. A thread protector comprising a sleeve shaped to lie against and longitudinally of the pipe member to which it is to be applied, said sleeve having its edge nearest the end of the pipe to be protected turned at an angle to the body thereof to form a thread adapted to engage the thread of the pipe member, and a cap having a skirt engaging the sleeve and a portion shaped to extend over and engage and protect the end of the pipe, the sleeve and the skirt being humped to form a bead adapted to lock them together.

3; A thread protector comprising a sleeve shaped to lie against and longitudinally of the pipe member to which it is to be applied, said sleeve having its edge nearest the end of the pipe to be protected turned at an angle to the body thereof to form a thread adapted to engage the thread of the pipe member, and a cap having a skirt engaging the sleeve and a portion shaped to extend over and engage and protect the end of the pipe, the sleeve and the skirt being humped to form a bead adapted to lock them together, the portion of the cap between where it to extend over and engage and protect the end of the pipe, the sleeve and the skirt being humped to form a bead adapted to lock them together, the portion of the cap between where it engages the end of the pipe member and the bead being adapted to lie clear of the pipe member, and having drain openings therein, the drain openings being so located that water cannot accumulate inside the roll portion to a depth suflicient to wet the pipe.

HAROLD E. MCCRERY. 

